The Tapping Finger Identification (TFI) technology disclosed in U.S. patent application Ser. No. 11/361,858 by Ling Su et al. enables a new type of data entry solution by differentiating an input object from a group of candidate input objects. For example, TFI-enabled keyboards determine user input not only based on which key was pressed, but also on which of the user's fingers was used to press the key, as each key may be capable of selecting multiple symbols or functions. When provided with a virtual interface, TFI-enabled systems permit users to touch type or perform multi-touch input on invisible devices on a work surface or even “in the air”.
While fingers, as an obvious example to facilitate understanding, are frequently used in the discussion, it is worth noting that other types of input objects may also be used.